The human homologous pairing protein HPP-1 is specifically stimulated by the cognate single-stranded binding protein hRP-A

S. P. Moore, L. Erdile, T. Kelly, R. Fishel

Research output: Contribution to journalArticle


Homologous pairing and strand exchange of DNA are catalyzed by the human homologous pairing protein HPP-1 in a magnesium-dependent, ATP-independent reaction that requires homologous DNA substrates and stoichiometric quantities of HPP-1. Here we show that the addition of the purified human single-strand binding (SSB) protein hRP-A to the reaction mixture stimulates the rate of homologous pairing 70-fold and reduces the amount of HPP-1 required for the reaction at least 10-fold. The identification of hRP-A as a stimulatory factor of HPP-1-catalyzed reaction was facilitated by its recognition as a member of a high molecular weight complex of recombination components. Neither the Escherichia coli SSB protein, bacteriophage T4 gene 32 protein, nor the highly conserved Saccharomyces cerevisiae yRP-A SSB protein could substitute for hRP-A in this stimulation. Because only the cognate SSB was capable of stimulating HPP-1, these results suggest that eukaryotes depend on unique and specific interactions between DNA recombination components.

Original languageEnglish (US)
Pages (from-to)9067-9071
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number20
StatePublished - Jan 1 1991



  • DNA repair
  • DNA replication
  • genetic recombination
  • recombination complex

ASJC Scopus subject areas

  • General

Cite this